It is proposed to conduct a mechanistic study on the hydrogen-transfer step of the NADH-dependent dehydrogenase reactions in the enzymatic as well as in vitro model systems, in the hope of obtaining evidence for or against the possible radical intermediates. The experimental approach to be employed is utilization of the extremely rapid radical rearrangements and isomerizations as probe for the possible radical intermediacy. The immediate objectives of the proposed research include a) preparation and chemical study of a number of carbonyl compounds which are capable of rapid radical reactions, and b) their utilization in the enzymatic and in vitro model reactions of NADH-dependent dehydrogenase activity.